1. Field of the Invention
The present invention relates to a scroll type fluid machine.
2. Description of the Related Art
As related art in the field of invention of the present invention, JP-A-2004-138056 and JP-A-2006-017013 can be cited.
In JP-A-2004-138056, a scroll type fluid machine is described in which plural numbers of projections are arranged on a peripheral surface of a wrap section of at least one of scrolls.
In JP-A-2006-017013, a scroll type fluid machine is described in which thin sections are formed in a predetermined angle range on the inner peripheral surface or the outer peripheral surface of the wrap section of the fixed scroll.
In the scroll type fluid machine of JP-A-2004-138056, the plural numbers of projections are provided so as to enhance sealing performance in a compressing period, and thus, compression efficiency is improved.
Here, in the scroll type fluid machine, the wrap section formed in the scroll is thermally deformed by compression heat at the time of operation. Deformation of the wrap section by thermal deformation is not uniform depending on the position in the peripheral direction due to the effect of the cooling fins and the like provided on the back side surface of the wrap section, the gap between the wrap sections of the opposed scrolls is large in some portion, and is small in other portion.
Therefore, for example, as described in JP-A-2006-017013, by forming the thin sections for the portions where the gap of the wrap sections of the opposed scrolls became small due to the thermal deformation, the compression efficiency was improved while preventing contact of the wrap sections to each other at the time of operation.
However, when, in view of the effect of the thermal expansion at the time of operation, the wrap sections were kept from coming in contact with each other, the gap between the wrap sections of the opposed scrolls became large beyond necessity. In particular, leakage of the compressed fluid at the time of the start of operation increased, the sealing performance of the compression chamber could not be enhanced, and the compression efficiency could not be improved.